Drain valve



FIG. 1 is an oblique view of the drain valve.

FIG. 2 is a right view of the drain valve.

FIG. 3 is a left view of the drain valve.

FIG. 4 is a front view of the drain valve.

FIG. 5 is a back view of the drain valve.

FIG. 6 is a top view of the drain valve; and,

FIG. 7 is a bottom view of the drain valve.

The broken lines shown in the figures are included for the purpose of illustrating portions of the drain valve and form no part of the claimed design. 

CLAIM The ornamental design for a drain valve, as shown and described. 